The Thermodynamic Model on Paraffin Wax Deposition Prediction

Baojun Liu,Wanting Sun,Chengting Liu,Liping Guo

doi:10.4236/eng.2015.712072

Abstract

In process of crude oil production and transportation, wax and other solid deposition issues have a significant impact on oilfield production. Solid precipitation not only reduces the production efficiency and increases the cost of production. Therefore, there is a need to study the rate of paraffin wax deposition and cloud point temperature in order to guide the oil field control the paraffin wax deposition. In this paper, we use the Flory theory of polymer solution to correct the liquid activity coefficients, and regular solution theory to correct for the non ideality of the solid mixture, and we consider the impact of isoparaffin. Finally, thermodynamic model is established. The actual example calculation shows that the forecast results of this model are more accurate.

Highlights

The Thermodynamic ModelWhen the phase equilibrium of gas, liquid, solid phase is reached [3]. where fiV = xiV φiV p
In process of crude oil production and transportation, wax and other solid deposition issues have a significant impact on oilfield production
Paraffin wax is mainly composed by the n-alkane, but contains a small amount of isoparaffin, cycloalkane and aromatic

Summary

The Thermodynamic Model

When the phase equilibrium of gas, liquid, solid phase is reached [3]. where fiV = xiV φiV p. Use the Flory theory of polymer solution to correct the liquid activity coefficients, the calculation formula as follows [4]. Among which P stands for alkane, N stands for cycloalkane, A stands for aromatic. Their molecular interaction coefficients are as follows:. Paraffin wax is mainly composed by the n-alkane, but contains a small amount of isoparaffin, cycloalkane and aromatic. For these non-normal paraffin, their melting point and other properties are very different from the n-alkane, the melting point of normal paraffin wax decreases obviously when a branch is added.

The Example Calculation and Results

Conclusions